Home page
SPONSOR AD

Support our Vendors!  |  Advertise Here

Topic: '72 Wiper Door Malfunction

in Forum: C3 Body


Already a Member?
Login
Not yet a Member?
Register for Free!

'72 Wiper Door Malfunction (1/13)
 3/13/09 2:16am
rdupler2
Former Member

Send Private Message

Hurst, TX - USA

Vette(s):
1972 Corvette Coupe. 350/200 Automatic with PS/PB/PW and A/C. Beautiful Bryar Blue. Unmolested original. Shooting for NCRS Top Flight someday.


Joined: 10/14/2007
Posts: 173

Had the '72 for a just about a year now and got caught in a unexpected shower Tuesday evening (first time I've gotten caught in the rain in it!) I had never used the wipers except when testing them prior to purchase. I had turned the wipers off about a block from home and the wiper door retracted and seated just as it should. Pulled it into the garage and turned off the engine and all seemed well. 3-4 minutes after I turned off the engine, the wiper door decided to raise up approx 1/2" and stay there. I started it back up and the wiper door closed again but every time I turn off the engine the same thing happens.
Seems like if it was a leak then the door would raise up all the way after shutting down.

I'm sure this is not new to you veterans out there so someone can supply me a quick fix....rightThumbs%20Up?
Our Sponsors help support C3VR
'72 Wiper Door Malfunction (2/13)
 3/13/09 8:10am
Adams' AppleLifetime Member
Lifetime Member
Moderator
Send Private Message

Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


Joined: 11/8/2003
Posts: 20126

Roger, the most likely culprit is the vacuum check valve.
This valve is in the vac. line that comes off of the back of the intake, just behind the carb. It is a metal, pie-pan shaped object, with one vac. line on one side, and two on the other. When this valve malfunctions, it can cause the wiper door to raise all the way up, or just a little when you turn the engine off.
The other thing that can cause this is the wiper door vacuum actuator relay valve, on the pass side fenderwell. Since you didn't have the problem before using the wipers that day, this may be your problem. The relay valve uses vac. to move a valve inside the relay, which routes the vacuum to either the "open" side or "close" side of the actuator outlets. If there is a leak inside the relay valve, it can let the valve move slightly when you turn the engine off, and allow vac. to the "open" side.


Somewhere here, there are a couple of threads on both of these items, and some testing info. If you want, I can e-mail you some vacuum checking info...

______________

Joel Adams
C3VR Lifetime Member #56    

My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

'72 Wiper Door Malfunction (3/13)
 3/13/09 11:23am
MikeMc71
Former Member

Send Private Message

Tucson, AZ - USA

Vette(s):
1970 White L-46 Air Roadster, 1971 White LT1 Coupe, 1971 Red Auto Air Coupe, 383 stroker, 430 HP, 2002 Millennium Yellow Auto Coupe


Joined: 10/7/2007
Posts: 341

This is the other valve to check. Its the wiper arw control valve. Its located on the passanger side, under the wiper door. The passanger side wiper contacts this in order to tell the system that its OK to close the door. If its leaking, or stuck so it won't fully open, it can also cause the door to open.

______________

'72 Wiper Door Malfunction (4/13)
 3/13/09 11:44am
rdupler2
Former Member

Send Private Message

Hurst, TX - USA

Vette(s):
1972 Corvette Coupe. 350/200 Automatic with PS/PB/PW and A/C. Beautiful Bryar Blue. Unmolested original. Shooting for NCRS Top Flight someday.


Joined: 10/14/2007
Posts: 173

Wow, Joel and Mike those were great repliesSmile!  I believe I found the line u r talking about Joel.  It is the 1/2" vacuum line coming from the elbow fitting off the manifold behind the carb and going down to the white plastic fitting and then to the metal check valve? 
 
Joel can you e-mail me the vacuum troubleshooting instructions you mentioned?  Also does anyone have an electronic version of a vacuum system diagram?
'72 Wiper Door Malfunction (5/13)
 3/13/09 12:24pm
rraider1
Former Member

Send Private Message

Woodland, WA - USA

Vette(s):
1977 T-Top,350,Auto Black Ruby Pearl,Steeroids R&P conversion


Joined: 10/14/2003
Posts: 1165

'72 Wiper Door Malfunction (6/13)
 3/13/09 1:15pm
Adams' AppleLifetime Member
Lifetime Member
Moderator
Send Private Message

Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


Joined: 11/8/2003
Posts: 20126

Roger...I e-mailed the info earlier today...."You've got Mail"...
If it didn't come thru, let me know, and I'll re-send it.

And yes, the metal check-valve is what I was referring to...it will cause the door to open a little, or all the way, depending on HOW it is malfunctioning. I say take a trip over to Phil's house, and do a little "parts swap"...

Just kiddin...but it would be an easy test to see if that is in fact the problem.

______________

Joel Adams
C3VR Lifetime Member #56    

My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

'72 Wiper Door Malfunction (7/13)
 3/13/09 2:01pm
rdupler2
Former Member

Send Private Message

Hurst, TX - USA

Vette(s):
1972 Corvette Coupe. 350/200 Automatic with PS/PB/PW and A/C. Beautiful Bryar Blue. Unmolested original. Shooting for NCRS Top Flight someday.


Joined: 10/14/2007
Posts: 173

Robert, thanks for the link to the picture!  That is great info.  I appreciate that.
 
Joel, me thinks you have a good idea.  Phil's at work today and I have the key to his garage Evil%20Smile LOL!!!!!!!!!!
 
I called and talked to "Mike" at Bairs.  He was confident it was the check valve also.  He's fixed me up with the check valve and a new filter for that line - a little over $20 bucks.
 
Thanks Joel very much for the pictures you sent.  That is some great info also.  My wife was in the e-mail before me this morning and she had clicked it and it didn't show up in BOLD print in the inbox anymore.  That's why I overlooked it this morning. 
 
Roger
'72 Wiper Door Malfunction (8/13)
 3/13/09 10:52pm
Adams' AppleLifetime Member
Lifetime Member
Moderator
Send Private Message

Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


Joined: 11/8/2003
Posts: 20126


Glad Mike was able to take care of ya, Roger!

______________

Joel Adams
C3VR Lifetime Member #56    

My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

'72 Wiper Door Malfunction (9/13)
 3/24/09 5:48pm
rdupler2
Former Member

Send Private Message

Hurst, TX - USA

Vette(s):
1972 Corvette Coupe. 350/200 Automatic with PS/PB/PW and A/C. Beautiful Bryar Blue. Unmolested original. Shooting for NCRS Top Flight someday.


Joined: 10/14/2007
Posts: 173

Well I replaced the check valve and filter in the vacuum line off the intake manifold and it did not fix the problemUnhappy. Wiper door still raises back up about 3/8 inch 4 to 5 minutes after engine shutdown.

But this time, as I was bending over the right side of the car looking and wondering over the engine bay, I heard a sound like air rushing thru an orifice coming from under the right fenderShocked. It was the Wiper Vacuum Relay. I started the engine, let the wiper door seat and shut the engine down. I hear the noise between the 4 and 5 minute mark every time just before the wiper door raises up.
 
Do you think it's a bad wiper vacuum relay or something between the relay and the bypass valve/solenoid valve arrangement under the dash that is the culprit????
'72 Wiper Door Malfunction (10/13)
 3/24/09 9:19pm
Adams' AppleLifetime Member
Lifetime Member
Moderator
Send Private Message

Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


Joined: 11/8/2003
Posts: 20126

It's the relay leaking...

______________

Joel Adams
C3VR Lifetime Member #56    

My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

'72 Wiper Door Malfunction (11/13)
 3/26/09 11:54pm
rdupler2
Former Member

Send Private Message

Hurst, TX - USA

Vette(s):
1972 Corvette Coupe. 350/200 Automatic with PS/PB/PW and A/C. Beautiful Bryar Blue. Unmolested original. Shooting for NCRS Top Flight someday.


Joined: 10/14/2007
Posts: 173

Joel, Thanks for the thought.

I was reading on another forumShocked that the small hose going to the actuator housing of that relay is the "control" line.  Vacuum to that line causes the valve to operate and send vacuum to the front side of the wiper actuator on the firewall.  If you lose vacuum on that relay actuator e.g., if that control line or a device in that control line leaks, then you will lose vacuum on the relay actuator and it will move in the other direction via spring force and thus cause the relay valve to send vacuum to the other side of the wiper actuator thus opening the wipre doorWacko
 
Oh well Phil and I will check it out asome more this weekend and will let you know what we find.  Might be able to "borrow" the relay from Phil's car and test since his being a '69 it is very easy to get to.
'72 Wiper Door Malfunction (12/13)
 3/27/09 8:05am
Adams' AppleLifetime Member
Lifetime Member
Moderator
Send Private Message

Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


Joined: 11/8/2003
Posts: 20126

That's exactly how it works...spring and all! The valve has a "at rest" position. This position is supposed to leave the wiper door in the open position if there is a problem with the vac. system...sort of a "fail-safe" deal.

______________

Joel Adams
C3VR Lifetime Member #56    

My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

'72 Wiper Door Malfunction (13/13)
 3/27/09 11:44am
F4GaryGold Member
Gold Member
Send Private Message

Grapevine, TX - USA

Vette(s):
1972 LT-1 convertible with factory air.


Joined: 8/26/2006
Posts: 1406

If you do replace the relay, don't forget to recheck the timing on the engine since you just plugged a vacuum leak.  I replaced mine just before we went on a Corvette Club cruise to Jefferson.  It pinged all the way over and back.  I couldn't figure it out until it just hit me.  Duh.

______________

   

Our Sponsors help support C3VR